Chantal van Son


Annotating Perspectives on Vaccination
Roser Morante | Chantal van Son | Isa Maks | Piek Vossen
Proceedings of the Twelfth Language Resources and Evaluation Conference

In this paper we present the Vaccination Corpus, a corpus of texts related to the online vaccination debate that has been annotated with three layers of information about perspectives: attribution, claims and opinions. Additionally, events related to the vaccination debate are also annotated. The corpus contains 294 documents from the Internet which reflect different views on vaccinations. It has been compiled to study the language of online debates, with the final goal of experimenting with methodologies to extract and contrast perspectives in the framework of the vaccination debate.


Resource Interoperability for Sustainable Benchmarking: The Case of Events
Chantal van Son | Oana Inel | Roser Morante | Lora Aroyo | Piek Vossen
Proceedings of the Eleventh International Conference on Language Resources and Evaluation (LREC 2018)

Scoring and Classifying Implicit Positive Interpretations: A Challenge of Class Imbalance
Chantal van Son | Roser Morante | Lora Aroyo | Piek Vossen
Proceedings of the 27th International Conference on Computational Linguistics

This paper reports on a reimplementation of a system on detecting implicit positive meaning from negated statements. In the original regression experiment, different positive interpretations per negation are scored according to their likelihood. We convert the scores to classes and report our results on both the regression and classification tasks. We show that a baseline taking the mean score or most frequent class is hard to beat because of class imbalance in the dataset. Our error analysis indicates that an approach that takes the information structure into account (i.e. which information is new or contrastive) may be promising, which requires looking beyond the syntactic and semantic characteristics of negated statements.


GRaSP: A Multilayered Annotation Scheme for Perspectives
Chantal van Son | Tommaso Caselli | Antske Fokkens | Isa Maks | Roser Morante | Lora Aroyo | Piek Vossen
Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16)

This paper presents a framework and methodology for the annotation of perspectives in text. In the last decade, different aspects of linguistic encoding of perspectives have been targeted as separated phenomena through different annotation initiatives. We propose an annotation scheme that integrates these different phenomena. We use a multilayered annotation approach, splitting the annotation of different aspects of perspectives into small subsequent subtasks in order to reduce the complexity of the task and to better monitor interactions between layers. Currently, we have included four layers of perspective annotation: events, attribution, factuality and opinion. The annotations are integrated in a formal model called GRaSP, which provides the means to represent instances (e.g. events, entities) and propositions in the (real or assumed) world in relation to their mentions in text. Then, the relation between the source and target of a perspective is characterized by means of perspective annotations. This enables us to place alternative perspectives on the same entity, event or proposition next to each other.

MEANTIME, the NewsReader Multilingual Event and Time Corpus
Anne-Lyse Minard | Manuela Speranza | Ruben Urizar | Begoña Altuna | Marieke van Erp | Anneleen Schoen | Chantal van Son
Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16)

In this paper, we present the NewsReader MEANTIME corpus, a semantically annotated corpus of Wikinews articles. The corpus consists of 480 news articles, i.e. 120 English news articles and their translations in Spanish, Italian, and Dutch. MEANTIME contains annotations at different levels. The document-level annotation includes markables (e.g. entity mentions, event mentions, time expressions, and numerical expressions), relations between markables (modeling, for example, temporal information and semantic role labeling), and entity and event intra-document coreference. The corpus-level annotation includes entity and event cross-document coreference. Semantic annotation on the English section was performed manually; for the annotation in Italian, Spanish, and (partially) Dutch, a procedure was devised to automatically project the annotations on the English texts onto the translated texts, based on the manual alignment of the annotated elements; this enabled us not only to speed up the annotation process but also provided cross-lingual coreference. The English section of the corpus was extended with timeline annotations for the SemEval 2015 TimeLine shared task. The “First CLIN Dutch Shared Task” at CLIN26 was based on the Dutch section, while the EVALITA 2016 FactA (Event Factuality Annotation) shared task, based on the Italian section, is currently being organized.

Unshared Task at the 3rd Workshop on Argument Mining: Perspective Based Local Agreement and Disagreement in Online Debate
Chantal van Son | Tommaso Caselli | Antske Fokkens | Isa Maks | Roser Morante | Lora Aroyo | Piek Vossen
Proceedings of the Third Workshop on Argument Mining (ArgMining2016)

Building a Dictionary of Affixal Negations
Chantal van Son | Emiel van Miltenburg | Roser Morante
Proceedings of the Workshop on Extra-Propositional Aspects of Meaning in Computational Linguistics (ExProM)

This paper discusses the need for a dictionary of affixal negations and regular antonyms to facilitate their automatic detection in text. Without such a dictionary, affixal negations are very difficult to detect. In addition, we show that the set of affixal negations is not homogeneous, and that different NLP tasks may require different subsets. A dictionary can store the subtypes of affixal negations, making it possible to select a certain subset or to make inferences on the basis of these subtypes. We take a first step towards creating a negation dictionary by annotating all direct antonym pairs inWordNet using an existing typology of affixal negations. By highlighting some of the issues that were encountered in this annotation experiment, we hope to provide some insights into the necessary steps of building a negation dictionary.


Hope and Fear: How Opinions Influence Factuality
Chantal van Son | Marieke van Erp | Antske Fokkens | Piek Vossen
Proceedings of the Ninth International Conference on Language Resources and Evaluation (LREC'14)

Both sentiment and event factuality are fundamental information levels for our understanding of events mentioned in news texts. Most research so far has focused on either modeling opinions or factuality. In this paper, we propose a model that combines the two for the extraction and interpretation of perspectives on events. By doing so, we can explain the way people perceive changes in (their belief of) the world as a function of their fears of changes to the bad or their hopes of changes to the good. This study seeks to examine the effectiveness of this approach by applying factuality annotations, based on FactBank, on top of the MPQA Corpus, a corpus containing news texts annotated for sentiments and other private states. Our findings suggest that this approach can be valuable for the understanding of perspectives, but that there is still some work to do on the refinement of the integration.